Conveyor systems



Aug. 17, 1965 s. JEFFERSON 3,200,937

CONVEYOR SYSTEMS Filed April 18, 1962 2 Sheets-Sheet 1 Aug. 17, 1965 s. JEFFERSON CONVEYOR SYSTEMS 2 Sheets-Sheet 2 Filed April 18, 1962 3,200,937 CONVEYOR SYSTEMS Sidney Jefferson, Ahingdon, England, assignor to United Kingdom Atomic Energy Authority, London, England j, Filed Apr. 18, 1962,Ser. N o. 188,454 Claims priority, application Great Britain, Apr. 27, 1961,

3 t 2 came. (Ci. 198-179) should be arranged as close together as possible to ensure an eflicient utilisation of the radiation from the source. r The conventional methods of side loading and unloading of packages on to the carrier are disadvantageous in that the carriers must be made considerably wider than the package dimensions with subsequent gaps between the packages on adjacent carriers. Similarly it is difficult to remove a package from a column of packages mounted on a carrier unless "a separate shelf is provided for each package with a resultant increase in the height of the column and clearance'spacebetween adjacent packages. The packages also tend to be insecurely mounted on the carriers with conventional side loading arrangements.

The object of the present invention is to provide a conveyor system for packages wherein the clearance space between adjacent package carriers in the system is minimized.

According to the invention a conveyor system for packages comprises an open ended structure pivotally mounted on a railway vehicle, openable and closeable package retaining means at one end of the container and means whereby, upon opening of the retaining means a package is inserted into the structure through one end and a package removed from the other end.

Preferably, the structure is a tubular container and suspended from an overhead railway and the package retaining means comprise an openable trap at the bottom of the container thereby enabling packages to be loaded through the bottom when the container is rotated to a horizontal position and aligned with a horizontal conveyor.

According to a further aspect of the invention a package carrier comprises an open ended container pivotally mounted on a railway vehicle, the fulcrum around which the container may pivot being positioned below the centre of gravity of the container and offset sideways relative to the centre of gravity such that when loaded the container may be moved from a horizontal alignment to a vertical alignment through a dead centre position, or vice-versa, and brought to rest by gravity biased abutment with a relatively fixed member on said vehicle.

To enable the nature of the invention to be more readily understood one embodiment of the invention will now be described by way of example with reference to the accompanying drawings. In the drawings:

FIG. 1 is an elevation of a carrier loaded with packages.

FIG. 2 is an elevation showing the carrier of FIG. 1 in the loading and unloading position.

Referring to the drawings the package carrier, which forms part of a mono-rail conveyor system, is suspended from a mono-rail 1 and comprises a railway vehicle portion provided with a U-shaped structure support frame 2 and an open ended structure 3. The structure hereafter United States Patent 0 referred to as a package container is tubular in form, of rectangular cross-section and pivotally attached to support frame 2 by fulcrum pins 4. The pins project from two opposed sides of the container and are journalled in the limbs of frame 2. The packages 5 are normally inserted through the bottom of the container and removed through the top end.

The method of propelling the carriers along the monorail is not shown but any of the conventional methods may be used for example chains or push rods.

To ensure that the container is easily rotated into a horizontal position for loading and unloading of packages it is desirable that the fulcrum pins are located no higher than the centre of gravity 6 of the loaded container. However if the fulcrum is arranged just below the centre of gravity and offset sideways relative to the vertical centre line of the container the resultant unstable condition of the container when vertical is advantageous. For example if the fulcrum was arranged just above the centre of gravity the container would hang vertically, but the forces maintaining the precise vertical position would be small and therewould be a tendency for the container to swing about the fulcrum during movement along the mono-rail. By offsetting the fulcrum relative to the vertical centre line of the container and providing a member 7, fixed to the frame 2, to act as a stop, the container may be biased into a vertical alignment and held against the stop thus reducing any tendency to swing around the fulcrum during movement along the mono-rail.

Locating the fulcrum below the centre of gravity ensures that as the container is rotated from the vertical to the horizontal loading and unloading position through the container dead centre position, it will become biased to the horizontal and abut a member 8 fixed to theframe 2. Since the centre of gravity isnow above the fulcrum and the container is prevented from further rotation by member 8, the container must remain inthis position until a righting force is applied to return the container to the vertical alignment.

It will be appreciated that member 7 may be eliminated if desired, since member 8 may be adapted toact also as the vertical alignment stop for the container.

The packages are retained in the container by spring biased wedge shaped stops or detent members 9. The stops are attached to leaf springs 10 secured to opposite sides of the container and the springs are so chosen that the spring stiifness is sufficient to support the package in the container whilst allowing packages to pass through the stops into the container without damage.

The loading and unloading station is arranged between two horizontal roller conveyor racks 12 and 13. Rack 12 conveys packages to the station and rack 13 acts as a disposal or delivery conveyor for irradiated packages.

In operation, the carrier is halted at the station and the container 3 rotated to a horizontal position and into alignment with the racks 12 and 13. A new package 14 is moved along the rack 12 and inserted in the end of the container by a pusher mechanism (not shown). As this new package 14 is pushed into the container the stops 9 are forced apart and a previously irradiated package is ejected from the other end of the container on to the delivery rack 13. The stops 9 are closed, the container is returned to the vertical position and the carrier moved along the monorail.

In a system which irradiates two packages per carrier, as described in our aforementioned patent specification, 2,155/60, after each passage through the irradiation cell one new package would be pushed into the lower end of the container, thus ejecting the package which had been through the cell twice and pushing the package which had been through once to the upper end of the container for its second passage.

tion of the specific'packages. .system the distribution of radiation from the source is The conveyor system of the invention may also be conveniently applied to an irradiation system in which specific packages are allowed a higher dose rate than other packages, for example to reduce the time required for irradia- In such an irradiation arranged whereby a package in a short centre section of the container, relative to the container height, receives .the full substantially uniform dose of radiation in one complete passage through the radiation zone, while packages in the upper and lower ends of the container each .receive a dose which varies from a maximum at one end ltainer in one movement through the radiation zone .whereas the other packages in the container would require two movements through the zone.

In an alternative mode of operation, the container 3 may be loaded with an uneven number of packages, for example five package units. The upper and lower packages in a five package container are preferably each two units high, i.e. two long packages and a short centre package per container. After the container has completed a movement through the radiation zone it is halted at the loading and unloading station, and a new short package and a new long package are inserted respectively through the bottom of the container. The irradiated upper package and the centre package are consequently ejected through the other end, the long package having completed 'two movements through the radiation zone and the short 1. A package carrier for use in a conveyor system for h a package irradiaiton plant, comprising:

(a) a tubular container mounted on a trolley and open at its opposite longitudinal ends,

(b) a fulcrum on the trolley around which the container may pivot,

(c) said fulcrum being positioned below the center of gravity of the container and offset sideways relative to the center of gravity such that when loaded the container may be moved from a package loading horizontal alignment to a vertical alignment for package transit, through a dead center position, or vice versa, and brought to rest by gravity biased abutment with a relatively fixed member on the trolley, 1

(d) abutment means on said trolley against which said container rests in said two positions, a

(e) and package retaining means at the bottom of said container.

2. A package carrier for a conveyor system comprising:

(a) a trolley including means for supporting said trolley from an overhead rail,

(b) a package container carried by said trolley and mounted for pivotal movement about a horizontal axis from a vertical position to a horizontal position,

(c) said container being open at least at its lower end,

considered when the container is vertically positioned, and including means at said lower end for retaining packages in said container,

(d) said horizontal axis being positioned below the center of gravity of said container and offset sideways relative to the center of gravity,

(e) and abutment means on said trolley for supporting said container in said horizontal or vertical position against the bias of gravity.

References Cited by the Examiner UNITED STATES PATENTS 8/20 Gunn 294-69 6/56 Freeman 29473 

1. A PACKAGE CARRIER FOR USE IN A CONVEYOR SYSTEM FOR A PACKAGE IRRADIATION PLANT, COMPRISING: (A) A TUBULAR CONTAINER MOUNTED ON A TROLLEY AND OPEN AT ITS OPPOSITE LONGITUDINAL ENDS, (B) A FULCRUM ON THE TROLLEY AROUND WHICH THE CONTAINER MAY PIVOT, (C) SAID FULCRUM BEING POSITIONED BELOW THE CENTER OF GRAVITY OF THE CONTAINER AND OFFSET SIDEWAYS RELATIVE TO THE CENTER OF GRAVITY SUCH THAT WHEN LOADED THE CONTAINER MAY BE MOVED FROM A PACKAGE LOADING HORIZONTAL ALIGNMENT TO A VERTICAL ALIGNMENT FOR PACKAGE TRANSIT, THROUGH A DEAD CENTER POSITION, OR VICE VERSA, AND BROUGHT TO REST BY GRAVITY BIASED ABUTMENT WITH A RELATIVELY FIXED MEMBER ON THE TROLLEY, (D) ABUTMENT MEANS ON SAID TROLLEY AGAINST WHICH SAID CONTAINER RESTS IN SAID TWO POSITIONS, (E) AND PACKAGE RETAINING MEANS AT THE BOTTOM OF SAID CONTAINER. 